In the printing industry a number of rollers and drums are used for various purposes. Drums in printing machines are often equipped with sleeves that have various layers, and depending upon the use of the drum, fulfill different functions. For example, imaging cylinders in a photoelectric printing machine are equipped with photoelectric sleeves, that are capable of accepting a latent electrostatic image to which toner particles adhere, whereby a printed image is created that is transferred to a printing medium when the imaging cylinder is rolled over the printing medium. The sleeves on the drums are replaced from time to time, whereby the drum as the element that supports the sleeve, continues to be used, and is not replaced.
Prior art provides, for example, a compressed air mechanism for replacing the sleeve, which makes compressed air available from inside the drum. The diameter of the sleeve is enlarged by the compressed air, the strength of the bonding between the sleeve and the drum is diminished, and the sleeve that is ordinarily tightly held against the drum, can be slid off. A disadvantage of this prior art solution is the fact that a compressed air apparatus, along with a compressor for providing compressed air at several bars, must be available.
With the prior art process, not all kinds of sleeves can be securely attached to a drum. At a certain thickness and with certain characteristics of the material, the process for replacing the sleeve from the drum by compressed air fails to work. For example, sleeves made of thick metal cannot be slid onto a drum. The result is that metal sleeves with a smaller wall thickness are manufactured in order to assure that they can be mounted on a drum, whereby the manufacturing process becomes more complicated and expensive.